Electro-thermal odor-releasing inks and methods for releasing odors from the same

ABSTRACT

The present invention is drawn to odor-releasing ink-jet inks and methods for releasing odors from printed images. The ink-jet ink includes an ink vehicle; an effective amount of an electro-thermal material dispersed within the ink vehicle; and an effective amount of an odor-releasing additive within the ink vehicle wherein an odorant is releasable from the odor-releasing additive upon substantial activation of the electro-thermal material.

This is a divisional of copending application Ser. No. 09/978,259 filedon Oct. 15, 2001 now U.S. Pat. No. 6,648,950, which is herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to ink-jet inks. Moreparticularly to odor-releasing ink-jet inks wherein the odor can bereleased at a desired time and/or location.

BACKGROUND OF THE INVENTION

Thermal ink jet printers, provide an effective means of propelling inkjet inks onto various media including paper. These printers canaccomplish this by using resistive heater elements for heating the inkto a boil, and propelling the ink through an overlying orifice plate.Such printers as typified by the Hewlett-Packard DeskJet™ and DesignJet™printers, are desirable for use for several reasons. For example,thermal ink jet printers have a relatively fast throughput while beingrelatively inexpensive to run. Additionally, these printers arerelatively easy to use, and the ink is easily replaced.

There are several reasons that ink-jet printing has become a popular wayof recording images on various media surfaces, particularly paper. Someof these reasons include low printer noise, capability of high-speedrecording, and multi-color recording. Additionally, these advantages canbe obtained at a relatively low price to consumers. However, thoughthere has been great improvement in ink-jet printing, accompanying thisimprovement are increased demands by consumers in this area, e.g.,higher speeds, higher resolution, full color image formation, increasedstability, new applications, etc. In addition to these challenges, thereis increased market pressure to provide ink-jet inks for new andcreative applications.

Many experimental electro-conductive inks have been and are beingproduced for various purposes. In order to produce a conductive ink,conductive substances are integrated into the ink system. Pigmentsand/or dyes can be optionally added if the desire is to visualize theconductive path being created. As a practical matter, in order for anink to be conductive, the conducting substances should be present in theink matrix such that the individual particles are large enough and closeenough together to functionally allow for current flow. Appropriatesubstances can include first-grade conductors such as metal and preciousmetal powder and/or carbon powder. Though metal and precious metalpowders generally provide for higher conductivity that carbon powder,they also are more prone to oxidation, corrosion, and in some cases,migration. Precious-metal powders can also be expensive. Conversely,carbon, does not exhibit these problems.

No matter what electro-conductive material is used to create theelectro-conductive ink, by selecting the appropriate ink vehicles and/orother components, e.g., polymers, surfactants, etc., easy processing,good adhesion and high mechanical and chemical resistance can beachieved.

In the scented ink area, many different types of inks have been preparedthat can emit odors. For example, a printed image known by its commonname “scratch and sniff” is one such technology. The basic idea behindscratch and sniff technology is to take the aroma generating chemicaland encapsulate it in gelatin or plastic microspheres through a processknown generally as microencapsulation. Such gelatin or plastic spherescan be as small as a few microns in diameter. Thus, when themicrospheres are mechanically ruptured by scratching, the odor isreleased.

Other odor-containing inks have also been prepared that contain an odorthat is detectable when exposed to a surrounding environment. Such inkshave been used in felt-tipped pens wherein the odor is not noticeable tothe user until a pen cap is removed from the pen and/or the ink ispresented on a substrate. However, the odor of such an ink, once printedon a substrate, does not last for a significant period of time as may bedesired by the user.

SUMMARY OF THE INVENTION

It has been recognized by the inventors that it would be desirable toprovide inks, particularly for use in ink-jet ink printers, that areboth electrically conductive and odor-releasing. Thus, by utilizing sucha composition, or composition equivalent, odor can be released from anink printed on a substrate at a desired time. Additionally, an odor canbe preserved over a period of time comparable to the scratch and snifftechnologies, without the requirement that mechanical scratching occurto release the odor.

Specifically, the present invention is drawn to odor-releasing inks,particularly ink-jet inks. These odor-releasing inks provide to a usercontrol as to when and how much odor is to be released. Uniquely, theodor-releasing control is either thermal or electromagnetic, rather thanby mechanical releasing means. Specifically, an odor-releasing ink cancomprise an ink vehicle, an effective amount of an electro-thermalmaterial dispersed within the ink vehicle, and an effective amount of anodor-releasing additive wherein an odor is released from theodor-releasing additive upon activation of the electro-thermal material.

A method of releasing an odor from a printed image can comprise thesteps of providing a substrate having printed thereon an imagecomprising an electro-thermal odor-releasing ink, providing an energysource, and completing a circuit between the electro-thermalodor-releasing ink and the energy source, thereby releasing an odor.

For example, an odor-releasing article can comprise a substrate; and animage adhered to the substrate, wherein the image is electro-thermallyconductive, and the image contains or contacts an odor-releasingadditive, wherein upon electrical or thermal activation of the image, anodor is released from the odor-releasing additive.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the exemplary embodiments, andspecific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended. Any alterations and further modificationsof the inventive features illustrated herein, and any additionalapplications of the principles of the invention as illustrated herein,which would occur to one skilled in the relevant art and havingpossession of this disclosure, are to be considered within the scope ofthe invention.

The singular forms “a,” “an,” and, “the” include plural referents unlessthe context clearly dictates otherwise. Thus, for example, reference to“an ink” includes reference to one or more of such inks.

As used herein, “effective amount” refers to the minimal amount of asubstance or agent, which is sufficient to achieve a desire effect. Forexample, an effective amount of an “ink vehicle” is the minimum amountrequired in order to create ink, which will meet functional performanceand characteristic standards.

As used herein, “ink vehicle,” refers to the vehicle in which theodor-releasing additive and the electro-thermal material (and optionallya colorant) is placed to form an ink. Ink vehicles are well known in theart, and a wide variety of ink vehicles may be used with the inkcomposition of the present invention. Such ink vehicles may include amixture of a variety of different agents, including without limitation,surfactants, solvents, co-solvents, buffers, biocides, viscositymodifiers, surface-active agents, and water.

“Electro-thermal material” can include any substance within an inkvehicle that acts to provide energy flow through the ink, particularlywhen the ink has been printed on a substrate. The energy flow, e.g.,heat or electrical current, need only be sufficient to effectuate someodor release from an odor-releasing additive.

“Odor-releasing additive” includes any substance that can be added to anink vehicle or is present as part of a printed image for emitting anodor. Preferably, the odor-releasing additive is bound to, absorbed in,adsorbed on, or contained within a substrate such that the odor is notsubstantially released from the ink until being subjected to electricalor thermal activation, though this is not required. All that is requiredis that the odor-releasing additive release an increased amount ofodorant upon electrical or thermal activation of an electro-thermalmaterial within the ink vehicle or from a printed image.

The terms “activate,” “activation,” or “activated,” when used todescribe the condition of the electro-thermal material, includes changesthat occur within the ink that effectuates electrical or thermalconduction. Such activation is desired for the release of an odor fromthe odor-releasing additive.

“Image” does not necessarily require that what is printed on a substratebe visible. For example, an image within the context of the presentinvention can be printed on a substrate wherein the “ink” used does notimpart a visible color to the substrate, e.g, black printed on a blacksubstrate or the use of a colorless ink on any substrate. However, it ispreferred that an image described in conjunction with the presentinvention be visible.

With these definitions in mind, an odor-releasing ink-jet ink inaccordance with the present invention can comprise an ink vehicle; aneffective amount of an electro-thermal material dispersed within the inkvehicle; and an effective amount of an odor-releasing additive whereinan odorant is released from the odor-releasing additive upon substantialactivation of the electro-thermal material. Though not required, theodor-releasing additive can be a microparticle having adsorbed thereonor absorbed therein the odorant. In one embodiment, the microparticlecan be a pigment solid such as, for example, carbon black. If carbonblack is used, then carbon pigments such as PRINTEX 90 carbon black byDegussa, BLACK PEARLS 990 carbon black by Cabot, or PRINTEX XE-2 carbonblack by Degussa are functional. Alternatively, the microparticle can beselected from the group consisting of cationic resins, anionic resins,and nonionic resins that are not part of the pigment used to impartcolor. In fact, in one embodiment, there need not be a colorant present.For example, a colorless ink can be printed that imparts an odorant uponink activation that is not visible to the naked eye.

Though the odor-releasing additive can be any functional compositionthat provides an odor upon ink activation, in some applications, it maybe desirable that no odor be substantially detectable prior to itsintended release. Thus, compositions comprising microcapsules orhydrogels can be used that are electrically or thermally sensitive. Forexample, an electrochemical hydrogel containing a liquid odorant can beused. The hydrogel can contain an odorant for release upon substantialactivation of the printed ink-jet ink. Any suitable elecro- orthermosensitive hydrogel can be used such as, for example, hydratedpolymers selected from the group consisting ofpolyacrylamide-methacrylate polymers, styrene-ethylene/butylene-styrenetriblock polymers, ionic polymer-metal composites, poly(vinylalcohol)-poly(acrylic acid) polymers, and combinations thereof. In thisembodiment, the odorant can be contained within a solution entrainedwithin the hydrogel matrix, and the odorant can be released as thehydrogel shrinks or deswells due to electrical or thermal activation.

Alternatively, an odor-releasing agent can be encapsulated in amicrocapsule, vesicle, or liposome. In one embodiment, a hydrogelcontaining an odor releasing composition can be within the microcapsule,vesicle, or liposome. If a vesicle or liposome is used, then the vesicleor liposome can comprise a lipid surfactant having a hydrophilic end anda hydrophobic end, for example. An appropriate lipid surfactant caninclude fatty acid phosphate esters or glycerophospholipids. All that isrequired when using a microcapsule is that the microcapsule beconfigured to release the odorant upon appropriate energy activation,e.g., causing burst.

The electro-thermal material can be present in any amount that provideselectro- or thermal conductivity sufficient to release the odor from theodor-releasing additive. Practically speaking, the amount ofelectro-thermal material will generally be at from 5% to 15% by weightof the ink-jet ink composition, though more or less of a functionalamount can also be used. Appropriate electro-thermal materials caninclude members selected from the group consisting of carbon-conductivematerials, metal powders, precious-metal powders, ferro-alloys,semiconductive graphite carbon, organic metals such as polyanilines, andcombinations thereof. The electro-thermal material can include anorganic or inorganic salt such as those containing ions selected fromthe group consisting of ammonium, sodium, potassium, lithium, nitrate,nitrite, chloride, acetate, phosphate, sulfonate, and combinationsthereof. Under some circumstances, it may be desirable to have theelectro-thermal material physically or chemically bonded to theodor-releasing additive, though this is not required.

Appropriate odorants that can be used as part of the odorreleasing-additive (or solely as the odor releasing additive) includeany odorant that does not substantially impair the ink-jet ink frombeing ink-jettable. For example, vanillin[4-hydroxy-3-methoxybenzaldehyde], menthol[5-methyl-2-(1-methylethyl)cyclohexanol], eugenol[2-methoxy-4-(2-propenyl)phenol], and thymol[5-methyl-2-isopropylphenol] can be used.

The odor-releasing additive can be present in the odor-releasing ink atfrom 0.1% to 10% by weight, though this range is not intended to belimiting. For example, an appropriate amount of odor-releasing additivecan be used depending partly on the type of odor-releasing additive isselected, e.g., microencapsulated odor-releasing agents, swellableodor-releasing agents, microspheres comprised of odor-releasinghydrogels, microparticles having an odorant adsorbed thereon or absorbedtherein, etc.

A method of releasing an odor from a printed image is also providedwhich comprises the steps of providing a substrate having anelectrothermal odor-releasing image thereon; providing an energy source;and completing a circuit between the electro-thermal odor-releasingimage and the energy source, thereby releasing an odor. Though thismethod can use the ink-jet ink compositions described herein, any inkthat is electrically or thermally conductive that releases an odor uponelectrical or thermal activation can be used. For example, a printedimage from an offset printer that has conductive and odor-releasingproperties can be used with the present method. However, the ink-jetinks described herein can also be used to provide the image of thepresent method.

With this method, the energy source can be any energy source thatactivates the electro-conductive odor-releasing image. For example, abattery can be used to complete the printed circuit. Alternatively, theenergy source can be a heat source. The circuit can be completed by aswitch, or some other conductive object. For example, a conductiveelement such as, for example, a metal paper clip can be used to completea circuit between a battery and the printed image. In this manner, acircuit can be completed by electrically coupling the energy source tothe electro-thermal odor-releasing ink, thereby releasing an odor.

An odor-releasing article can also comprise a substrate; and an imageadhered to the substrate, wherein the image is electro-thermallyconductive, and the image contains or is in contact with anodor-releasing additive, and wherein upon electrical or thermalactivation of the image, an odorant is released from the odor-releasingadditive. Though the substrate can be any functional substrate, paper isa good substrate for use. Additionally, if paper is used as thesubstrate, an ultra-thin battery, such as is present with Power Paper™,can be used as the power source for activating the image. In oneembodiment, a porous protective coating can also be present over theimage to prevent unwanted odor loss from the odor-releasing additive. Anon-porous protective coating or layer that will be removed beforeactivation can also be present over the printed image.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the presentinvention. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the spiritand scope of the present invention and the appended claims are intendedto cover such modifications and arrangements. Thus, while the presentinvention has been shown in connection with what is presently deemed tobe the most practical and preferred embodiment(s) of the invention, itwill be apparent to those of ordinary skill in the art that numerousmodifications, including, but not limited to, variations in size,materials, chemicals, shape, form, function and manner of operation,assembly and use may be made, without departing from the principles andconcepts of the invention as set forth in the claims.

EXAMPLES

The following examples illustrate the preferred embodiments of theinvention that are presently best known. However, other embodiments canbe practiced that are also within the scope of the present invention.

Example 1

Carbon black (PRINTEX 90™ Carbon Black from Degussa) was treated with a25% solution of vanillin in methanol. The odorized carbon black was thenfiltered under light vacuum until the solvent was substantially removed.The odorized carbon black particles were then coated with awater-soluble polymeric dispersant. The vanillin odorized carbon blackpigment solids were then mixed with ink vehicle components and pHbalanced to about 8 to form an ink-jet ink composition. The compositioncomprised the following ingredients by weight:

 8% vanillin odorized carbon black  3% polymethacrylate copolymerwater-soluble dispersant  4% iron lignosulfate dispersant  2% potassiumnitrate  4% polyoxyether viscosity agent  1% alkoxy surfactant  7%2-pyrrolidone  3% diethylene glycol 68% deionized water

Example 2

Carbon black (BLACK PEARLS 880™ carbon black from Cabot) was treatedwith a 25% solution of menthol in acetone. The odorized carbon black wasthen filtered under light vacuum until the solvent was substantiallyremoved. The odorized carbon black particles were then coated with awater-soluble polymeric dispersant. The menthol odorized carbon blackpigment solids were then mixed with ink vehicle components and pHbalanced to about 8.5 to form an ink-jet ink composition. Thecomposition comprised the following ingredients by weight:

 8% menthol odorized carbon black  3% polymethacrylate copolymerwater-soluble dispersant  4% iron lignosulfate dispersant  2% potassiumnitrate  4% polyoxyether viscosity agent  1% alkoxy surfactant  7%2-pyrrolidone  3% diethylene glycol 68% deionized water

Example 3

Carbon black (PRINTEX XE-2™ from Cabot) was treated with a 25% solutionof vanillin in ethyl acetate. The odorized carbon black was thenfiltered under light vacuum until the solvent was substantially removed.The odorized carbon black particles were then coated with awater-soluble polymeric dispersant. The vanillin odorized carbon blackpigment solids were then mixed with ink vehicle components and pHbalanced to about 8 to form an ink-jet ink composition. The compositioncomprised the following ingredients by weight:

 6% vanillin odorized carbon black  2% polymethacrylate copolymerwater-soluble dispersant  4% microparticulate iron oxide particledispersant  5% lithium nitrate  5% polyoxyether viscosity agent  8%2-pyrrolidone 70% deionized water

Example 4

Carbon black (PRINTEX XE-2™ from Cabot) was treated with a 25% solutionof menthol in methanol. The odorized carbon black was then filteredunder light vacuum until the solvent was substantially removed. Theodorized carbon black particles were then coated with a water-solublepolymeric dispersant. The menthol odorized carbon black pigment solidswere then mixed with ink vehicle components and pH balanced to about 8.5to form an ink-jet ink composition. The composition comprised thefollowing ingredients by weight:

 6% menthol odorized carbon black  2% polymethacrylate copolymerwater-soluble dispersant  4% microparticulate iron oxide particledispersant  5% lithium nitrate  5% polyoxyether viscosity agent  8%2-pyrrolidone 70% deionized water

Example 5

Carbon black (PRINTEX 90™ Carbon Black from Degussa) was treated with a25% solution of eugenol in methanol. The odorized carbon black was thenfiltered under light vacuum until the solvent was substantially removed.The odorized carbon black particles were then coated with awater-soluble polymeric dispersant. The eugenol odorized carbon blackpigment solids were then mixed with ink vehicle components and pHbalanced to about 8 to form an ink-jet ink composition. The compositioncomprised the following ingredients by weight:

 8% eugenol odorized carbon black  3% phosphate ester water-solubledispersant  4% iron lignosulfate dispersant  2% potassium nitrate  4%polyoxyether viscosity agent  1% alkoxy surfactant  7% 2-pyrrolidone  3%diethylene glycol 68% deionized water

Example 6

Carbon black (PRINTEX XE-2 ™ from Cabot) was treated with a 25% solutionof thymol in acetone. The odorized carbon black was then filtered underlight vacuum until the solvent was substantially removed. The odorizedcarbon black particles were then coated with a water-soluble polymericdispersant. The thymol odorized carbon black pigment solids were thenmixed with ink vehicle components and pH balanced to about 8 to form anink-jet ink composition. The composition comprised the followingingredients by weight:

 6% thymol odorized carbon black  2% phosphate ester water-solubledispersant  4% microparticulate iron oxide particle dispersant  5%lithium nitrate  5% polyoxyether viscosity agent  8% 2-pyrrolidone 70%deionized water

While the invention has been described with reference to certainpreferred embodiments, those skilled in the art will appreciate thatvarious modifications, changes, omissions, and substitutions can be madewithout departing from the spirit of the invention. It is intended,therefore, that the invention be limited only by the scope of thefollowing claims.

1. A method of releasing an odor from a printed image comprising: (a)providing a substrate having printed thereon an image comprising anelectro-thermal odor-releasing ink; (b) providing an energy source; and(c) completing an electric circuit between the electro-thermalodor-releasing ink and the energy source, thereby releasing an odor. 2.A method as in claim 1 wherein the energy source is a battery or otherportable electrical storage device.
 3. A method as in claim 1 whereinthe energy source is an electric heater.
 4. A method as in claim 1wherein the electric circuit is completed by a switch.
 5. A method as inclaim 1 wherein the electric circuit is completed by electricallycoupling the energy source to the electro-thermal odor-releasing inkwith a conductive element.
 6. A method of releasing an odor from aprinted image comprising: (a) providing a substrate having printedthereon an image comprising an electro-thermal odor-releasing ink; (b)providing an energy source; and (c) completing a circuit between theelectro-thermal odor-releasing ink and the energy source by coupling theenergy source to the electro-thermal odor-releasing ink with aconductive element, thereby releasing an odor.
 7. A method as in claim 6wherein the energy source is a battery or other portable electricalstorage device.
 8. A method as in claim 6 wherein the energy source isheat.
 9. A method as in claim 6 wherein the circuit is completed by aswitch.